1. Field of the Invention
The present invention relates to a non-contact surface roughness-measuring device. More specifically, the present invention relates to a non-contact surface roughness-measuring device which measures a surface roughness of a measurement surface of a workpiece without contacting thereto employing a coordinate measuring machine.
2. Description of Related Art
A contact-type surface roughness-measuring device of which a stylus is abutted to the measurement surface of the workpiece and moved thereon, thereby detecting a displacement of the stylus as an electric signal and measuring a surface roughness of the measurement surface by processing the electric signal is conventionally known as a surface roughness-measuring device for measuring a surface roughness of a measurement surface of a workpiece. Also, a non-contact surface roughness-measuring device, in which a laser beam is irradiated to the measurement surface of the workpiece thereby measuring the surface roughness of the measurement surface by a reflection ratio of the laser beam is conventionally known.
In recent years, surface roughness of sliding sections of automobile engine parts is newly required to be measured in addition to conventional dimension measurement to improve distance/fuel ratio.
To meet the demand, it is considered to attach a probe of the non-contact surface roughness-measuring device to a (three-dimensional) coordinate measuring machine for measuring as an in-line equipment.
However, the following disadvantages occur by simply attaching the non-contact surface roughness probe to the coordinate measuring machine.
1 The non-contact surface roughness probe must be positioned at a predetermined distance from detection surface thereof to the measurement surface. However, the coordinate measuring machine cannot recognize the position of the detection surface, therefore, calibration is extremely difficult. PA1 2 Since the non-contact surface roughness probe is made to detect only roughness, even when the non-contact surface roughness probe touches the workpiece, the coordinate measuring machine cannot detect contact therebetween, which can result in damage in the non-contact surface roughness probe and the coordinate measuring machine itself.